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I need help with knowing which shaded region is the solution on the graph

I need help with knowing which shaded region is the solution on the graph-example-1
User Marvb
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1 Answer

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Solution:

Given the system of inequalities:


\begin{gathered} y<3x-5\text{ --- (1)} \\ y\ge-3x+2\text{ ----(2)} \end{gathered}

From inequality (1),


\begin{gathered} \text{when x=0, we have} \\ y<3(0)-5 \\ \Rightarrow y<-5 \\ \text{when y=0, we have} \\ 0\ge-3x+5 \\ \text{subtract 5 from both sides }of\text{ the inequality} \\ 0-5\ge3x+5-5 \\ -5>3x \\ divide\text{ both sides by the coeff}icient\text{ of x, which is 3.} \\ \text{thus,} \\ -(5)/(3)>(3x)/(3) \\ \Rightarrow-(5)/(3)>x \end{gathered}

From inequality (2),


\begin{gathered} \text{when x=0, we have} \\ y\ge-3(0)+2 \\ \Rightarrow y\ge2 \\ \text{when }y=0,\text{ we have} \\ 0\ge-3x+2 \\ \text{subtract }2\text{ from both sides of the inequality} \\ 0-2\ge-3x+2-2 \\ \Rightarrow-2\ge-3x \\ \text{divide both sides by the coefficient of x, which is -3.} \\ \text{thus,} \\ -(2)/(-3)\ge-(3x)/(-3) \\ \Rightarrow x\le(2)/(3) \\ \text{Note: when the coefficient of the unknown is negative, the inequality sign changes when dividing.} \end{gathered}

Thus, plotting these range of values of x and y on a graph, we have

In the above plot, the intersections of the shaded regions of the inequalities is the solution to the system of inequalities.

I need help with knowing which shaded region is the solution on the graph-example-1
User Artem Kachanovskyi
by
5.0k points